Closed section louver for material separating apparatus



Nov. '17, 1959 R. E. ROGERS 1 CLOSED SECTION LOWER FOR MATERIALSEPARATING APPARATUS Filed May 13, 1955 v INVEN'fOR R0554? fl/PoangsTORNEYST CLOSED SECTION LOUVER FOR MATERIAL SEPARATIN G APPARATUS RobertE. Rogers, Sausalito, Califi, assignor to Harvestaire, Inc., Oakland,Calif., a corporation of California 7 Application May '13, 1955, SerialNo. 508,031

7 Claims. 01409-144 This invention relates to material separatingapparatus in which particles of entrained material in a fluid carrierare segregated by virtue of differences in the unit mass weights of therespective particles; and more. particularly, the present invention isdirected towards a louver attachment for use in a material separatingcharnber designed for segregating materials of very slight densitydifferentials.

- In my copending application, Serial. No. 508,189, filed May 13, 1955,there is disclosed an open section type of louverin which anunobstructed vertical passage is provided between adjacent vanes of thelouver. This is clearly distinguishable from a closed section type oflouver in which there is a lateral overlapping of the vanes, this lattertype of construction being generally disclosed in United States LettersPatent 2,638,181, 2,638,218 and 2,638,219. These louvers are provided inconnection with separating equipment adapted to receive a continuousflow of fluid having material particles entrained therein, such flow andmaterial being subjected in a conical separating chamber to variousforces whereby selected components (namely the heavier values) areallowed to gravitally descend through the louver and out of theseparating chamber, while the remaining mixture of rejected particles(tailings) and the carrier fluid are arrested from further gravitalmovement by the louver and are then caused to move upwardly and bedischarged out of the chamber. While the louver construction disclosedin said patents as well asin my copending application areall designedfor the same general purpose, ithas been found that where there is avery slight densitydifferential between the groups of particles to beseparated, an open section louver is clearly impractical, as there is atendency for even the lighter density tailings to pass between the vanesof the louver and become undesirably intermingled with the grain values.Likewise, although the louvers disclosed in the above identifiedpatents, owned by a common assignee with the instant application, are.of the closed section type, it has been found difficult to adequatelycontrol the mechanism so that only the grain or desired values passdownwardly through the louver and the lighter or less dense materialspass upwardly for discharge, without some intermingling of the'- if:

heavierand lighter density particles. It is a principal object of thepresent invention to' provide material separating apparatus in which aseparating chamber is utilized having a louver construction, includ inga plurality of vanes, positioned so as to permit separation of particlesof material having very small density differentials.

Another object of thisinvention is to provide separa tion equipment ofthe character described in which the less dense materials, even thoughinitially passing downwardly and partially through the louver, will becaused grainror other valued par- .wallss, and a lower axially aligneddischarge opening s i 2 construction of the character describedincluding a central imperforate baflle portion and a plurality ofuniquely shaped and arranged vanes, with alternate vanes havingdifferent forms and shapes than the other vanes of the louver. 1

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will'be set forth in the followingdescription of the preferred form of the invention which is illustratedin the drawing accompanying and forming'part of the specification. It isto be understood, however, that variations in the showing made by thesaid drawing and description may be adopted within the scope of theinvention as set forth in the claims.

Referring to said drawing:

Figurel is a side elevational view of a material separator provided withthe louver of the present invention.

Figure 2 is an'enlarged elevational view of the louver construction.

Figure 3 is a top plan view of the construction shown in Figure 2.

Figure 4 is an end view of several of the louver vanes, takensubstantially in the plane indicated by line 44 of Figure 3, but withthe vanes shown in parallel relationship rather than'radialrelationship, for purpose of clarity in the drawing and a betterunderstanding of the constructional details.

As hereinabove mentioned, the apparatus of the present invention hasbeen particularly designed for the separation'of groups of particles ofmaterial in a carrier fluid,

in which such particles have relatively low density difdensitydifferential, to have the tailings pass out with the values, or thegrain values pass out with the tailings. This is obviously anundesirable result, and by means-of the apparatus presently to bedescribed, it has been found that effective and eflicient separation maybe effected although possibly on a somewhat slower scale than when usingan open section louver construction as shown in the above identifiedpatent application. g

"The louver of the present invention is adapted to be used incooperation with a separator 6, having a tangential inlet 7, downwardlysloping conically formed side 9. Material carried in a carrier stream,such as air, is introduced tangentially into the inlet 7 through aconduit 12 'operatively associated with -a blower or threshing fan 13.In other words, the fan 13 is arranged to direct a I flow of fluid andentrained material in which the density fan 17, the duct enteringtheseparatorfrom the top there- 2, no further explanation as to details ofconstruction or opgroups are intermingled, into the separator 6 in whichit is acted uponby centrifugal and gravit-al forces to cause'adescen'sion of the entrained material of both lighter and heavier unitmass weights. As will be hereinafter described in detail, the heavierunit -mass weightsare adapted to be discharged-for collection throughthe opening-9 while the lighter components of the entrained material areadapted to be discharged through an axially extending "suction duct 16connected to a suitable suction of and with'the throat of the suctionduct 16 being axially spaced from the opening 9. The foregoingtypeofcon-- struction is found in the above identifiedpatents as well asin other more conventional separating equipment and erationis deemednecessary. As the material is hurled around in the separator,centrifugal force will cause the particles to engageand move. alongthednner peripheral surface of the side walls'8 orv substantiallyimmediately. adjacent theretoas they grav i."

Patented Nov. 17, 1959 seen in Figures 2 and4-of the drawing. The vanesare itally descend towards the discharge opening 9. If such dischargeopening was completely open, notwithstanding the provision of thesuction duct 16 many particles of even: lighter; density would}, falldownwardly through the:v openingtogether with theparticlesoffheavier'unit mass. 5 weights. In; order to prevent this condition,and efiect' a; thorough separation; between, theheavier and lighterdensity particles, the louver 21 is positioned across. the, separatoradjacentthe discharge. opening 9 so-asg to permit only the heavier ormore dense particles to gravitally 10 descend and be. discharged fromthe separator through the, louver; andpermit a vertical rising ofonlythe lighter particles under influence of; the suction blower-17; andtheduct 16. r

With particular reference to, Figures 2 through 4 ofthe. drawing, it.will be seen that; the louver 2l is positioned subjacent the suctionduct throat and the discharge, opening 9 and is provided with animperfor'ate centralbafile portion 22 havinga. shallow frusto-conicalbody 23. The axis of the louver as Well as-that ofthe frusto-conical boy. is alignedwith theaxis of the outlet 9 and the suction duct 16. Aswill be seen, the imperforate central portion has a diameter ofapproximately one-third of the overall louver'diameter, the lattercorresponding to the diametrical extent ofthe separating chamber at thelouver location. It is interesting to note that in the aforementionedcopending application, the imperforate central bafile occupies a muchlarger portion of the louver. It is believed that the reason for thisdistinction is that with an open section louver, a smaller annular spaceis adequate to fulfill the volume requirements. Indistinction to this,where a close section type of louveris uti-' lized, it is desirable tohave the same extend for the greatest radial extent possible withoutinterfering with the proper functioning of the louver. However, byhaving the imperforate central portion rather than permitting the louvervanes to extend to the louver axis, far more efiicient separation iseifected and there is little tendency for the heavier components topass'under the influence of the suction duct. Also, while the exactreasons-are somewhat obscure by reason of the difiiculty in determiningforces and operational patterns in a separator, the conical baffle asshown is more efficient than a Hat baflle plate but either of sucharrangements are believed an improvement on a completely open crosssectional area'at the throat.

The central imperforate portion 22 has a circular peripheral surface andsuch surface is spaced from the inner walls 8 of the separator so as toprovide an annular space 26 therebetween. Disposed within such space areaplurality of vanes 27 and 28, each of which extend radially from thebaffle periphery to the walls 8 of the separator. The vanes'27 are eachsubstantially identical and are extremely deep and are provided with agenerally vertical portion 29 which flares with an intermediate arcuateportion' into a generally horizontal portion 31, the latter terminatingin a common plane. The portion 31 defining thev horizontal extent of thevane does not quite approach the horizontal but is angularly, relatedthereto as'will be positioned relatively close to one another and eachof V the vanes 27 have a slight degree of overlapping. [Itzwill beappreciated that as the bottom of the separator as well as the louveritself tapers downwardly, the outermost edges 30 of the vanes aredisposed immediately adjacent the separator side walls and likewisetaper inwardly and downwardly.

Itwill be readily visualized that the vanes 27 by virtue; ofthe longvertical portions 29 are. far deeper than louvervanes heretoforeutilized, and as an important:feature of the invention, disposedbetweenv each pairof vanes 27. are intermediate vanes 28. Thellatter aresubstantially identical and. are positionedin. substantial par allel.relationshipto thevanes 27: but. extendlfrom: the. upper, ends thereotfor: only one=quarten of the vertical. 75

extent of vanes 27. Thus, every other blade 27 is what. might be termeda full vane and the alternate vanes 28 are of a substantially lesserdepth or less than one-half the depth of vanes 28. Furthermore, it willbe clear that the vertical extent of vanes 27 is substantially greaterthan the horizontal extent thereof, whereas in the case of vanes 28, thehorizontal'extent is the greater. This relationship is clearlyillustrated in Figure 4 of the drawing. Once again, the exact phenomenaof separation cannot be fully explained but it is believed that. anychaff, or light weight material which passes, for example, in the spaceA, may descend downwardly into the space B subjacent the lower edge of avane 28 and thence be caught in up draft or current of air created bysuction duct 16 and raised upwardly through the space C, thus followingthe path of the small arrows in Figure 4. The more horizontal or upperportions of all of the vanes are related to' thedirection of tangentialair flow in the sep'arator'likewis'e as illustrated. in Figure 4 so.that the. carrier. fluid and'material upon descending to the level ofthe louver, will first engage the portions 31 of the vanes, the lightermaterials then circulating up along the frusto-conical baffle member andthe heavier components will continue moving downwardly and pass inthespaces; A and C completely through the vanes for collection.

It is believedthat' from the foregoing description, the constructionaldetails as well as mode of operation of the. instant apparatus willbe'understood, and field tests have-clearly shownthe superiority of thistype of louver construction for separating particles of very minute;density diiferentials. With all uniform vane construc tion the highratio of. separation has been unobtainablei but by reason of thealternate deep and shallow over-r lappingvanes, in combination with theimperforate bathe: portion in the; central area of the. separator,optimum separation has been effected.

What isclaimed is:

1. Apparatus of the character described including a. separating chamberhaving a lower discharge opening, a louver having a central impe'rforateportion disposed adjacent said opening and'including a plurality ofvanes: extending radially outwardly from said central portion, each ofsuch vanes having a cross-sectional form with? the upper portionextending generally horizontally and a lower portion extending generallyvertically, alternate. vanes having a vertical extent in excess of thehorizontal..- extent thereof, and the other vanes having a horizontal;extentin excess of the vertical extent thereof.

2.. Apparatus as set forth in claim 1 in which SEtld'i alternate vaneshave a vertical extent substantially atv least twice, the verticalextent of their adjacent alternate.

vanes.

3. A louver construction for use with a material sepa-fi rator of thedry cyclone type comprising an imperforate. central portion, a pluralityof vanes extending radially outwardly from said imperforate member, thecross-sectional shape of each of said vanes including a generallyfiathorizontal upper portion and a generally vertical; lower portion and anintermediate arcuate portion, each. ofsaid horizontal portions overlyinga portion of its; adjacent vane, said vertical portions on alternatevanesi being substantially equal to each. other and .of greater verticaldepth, than the horizontal extent of thevanes, and'the vertical portionsof the other vanes beingsubstantially equal to each other and of alesser vertical extent than the vertical portions of said alternatevanes..

4. Apparatus as set forth in claim 3 in which each. of;

. said alternate vanes has approximately three times the verticalextentof an adjacent. vane.

5. In'separating apparatus having a. housing provided with. a.tangential inlet at the upper end thereof, a central discharge openingatthelower end thereof, and an.

- axially aligned. suction duct having a lower throat: open said housingintermediate said throat and opening, said louver having a substantiallyimperforate central portion axially aligned with said throat and openingand covering approximately one-third the diametrical extent of saidhousing at the louver location, a plurality of circumferentially spacedvanes mounted on said central portion and extending radially outwardlytherefrom, alternate ones of said vanes having a cross-sectional formincluding a horizontal portion substantially less than the verticaldepth thereof and being positioned relative to an adjacent vane so as tobe disposed in overlapping relationship thereto, and the other ones ofsaid vanes having a horizontal portion extending in excess of thevertical depth thereof.

6. Apparatus as set forth in claim 5 in which said central portion is offlat inverted frusto-conical configuration.

7. A louver construction for use with a material separator of the drycyclone type comprising a plurality of radially extending vanes, each ofsaid vanes having a cross-sectional shape comprising a substantiallyhorizontal upper portion and a substantially vertical lower portion,with the ends of the horizontal portions of the respective vanesvertically overlying a portion of its adjacent vane, and each alternatevane having a vertical depth at least twice as great as the verticaldepth of its 10 adjacent vane.

References Cited in the file of this patent UNITED STATES PATENTS 12,638,181 Gordon May 12, 1953 2,638,218 Simpson et a1 May 12, 19532,638,219 Gordon et a1. May 12, 1953

